Search for pair production of squarks or gluinos decaying via sleptons or weak bosons in final states with two same-sign or three leptons with the ATLAS detector

TL;DR

This paper reports a search for supersymmetric particles, specifically squarks and gluinos, decaying via sleptons or weak bosons, using the ATLAS detector data, and sets new exclusion limits up to 2.2 TeV.

Contribution

It introduces a comprehensive search strategy for SUSY particles in final states with multiple leptons, improving exclusion limits beyond previous results.

Findings

No significant excess over Standard Model expectations.

Gluino masses up to 2.2 TeV are excluded.

Squark masses up to 1.7 TeV are excluded.

Abstract

A search for pair production of squarks or gluinos decaying via sleptons or weak bosons is reported. The search targets a final state with exactly two leptons with same-sign electric charge or at least three leptons without any charge requirement. The analysed data set corresponds to an integrated luminosity of 139 fb$^{-1}$ of proton$-$proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Multiple signal regions are defined, targeting several SUSY simplified models yielding the desired final states. A single control region is used to constrain the normalisation of the $WZ$+jets background. No significant excess of events over the Standard Model expectation is observed. The results are interpreted in the context of several supersymmetric models featuring R-parity conservation or R-parity violation, yielding exclusion limits surpassing those from previous searches. In models considering gluino (squark) pair production, gluino (squark) masses up to 2.2 (1.7) TeV are excluded at 95% confidence level.